Solvay Fluor Und Derivate Gmbh

Kali-chemie Aktiengesellschaft

Solvay Sa

Solvay (societe Anonyme)

Solvaytflour Und Derivate Gmbh

Solvay Fluor and Derivate Gmbh

Werner Rudolph

Max Josef Braun

Johannes Eicher

Kerstin Eichholz

Ruediger Sander

Heinz-Joachim Belt

Hans-Walter Swidersky

Carsten Brosch

Joachim Massonne

Dirk Seffer

Karl-Heinz Fazniewscy

Alfred Borinski

Hans Buchwald

Boleslaus Raschkowski

Stefan Palsherm

Matthias Rieland

Ulrich Seseke-Koyro

Thomas Born

Alf Schulz

Dieter Naumann

Andreas Grossmann

Guenter Fernschild

Heinz-Rudi Feist

Karlheinz Fazniewscy

Ralf Herkelmann

Bernd Wilkes

Heinz Rudi Feist

Francine Janssens

Pascal Pennetreau

Wieland Tyrra

Heinrich Willenberg

Ulrich Hartmann

Guenter Fernschild, Deceased

Gunter Fernschild

Francine Jannssens

Wilhelm Pohlmeyer

Birgit Kock

Horst Bohm

Bernhard Schulte

Eckhard Hausmann

Frank Moewius

Veronika Radonz

Manfred Meisel

Joachim Frehse

The present invention relates to a process for the preparation of halogenated carboxylic anhydrides, e.g. for the preparation of trifluoroacetic anhydride. The preparation is achieved by reacting a halogenated carboxylic acid, e.g. trifluoroacetic acid, with sulfuric acid, oleum and/or disulfuric acid.

Process for the preparation of halogenated carboxylic anhydrides

The preparation of phosphorus pentafluoride and arsenic pentafluoride by reacting corresponding trihalides with elemental chlorine, bromine or iodine and also with hydrogen fluoride.

Method of preparing inorganic pentafluorides

The methyl and ethyl esters of trifluoroacetic acid or chlorodifluoroacetic acid can be prepared in a technically simple manner from the corresponding acid chlorides and methanol or ethanol, respectively, in the presence of an &ldquo;onium&rdquo; salt of the acid as a catalyst. The alcohol is used in a stoichiometric excess, namely the molar ratio of alcohol to acid chloride is selected such that operation is in the region of a two-phase reaction. One of the phases is formed by the desired ester product, which is obtained in a high purity without any distillation.

Two phase preparation of carboxylic acid esters

A method for producing carboxylic acid fluorides of the formula RCFXC(O)F, where X represents fluorine or chlorine, in good yields and with good selectivity for the carboxylic acid fluorides by reacting compounds of the formula RCFXCHFCl with oxygen by photochemical oxidation in the gaseous phase, preferably under sensitization with chlorine and using light having a wavelength &lgr;&gE;280 nm, which conditions make it possible to work without the use of pressure. Glass apparatus may be covered with a protective coating so as to protect it against traces of hydrogen fluoride. To this end, for example, heat-shrinkable sleeves made of light-permeable hydrogen fluoride-resistant material may be used. Polytetrafluoroethylene, polyfluoropropylene or a mixture thereof are especially suitable for this purpose. This type of protection is also suitable for other reactions such as photo-induced fluoro-dediazonation in hydrogen fluoride/pyridine for the production of aromatic compounds fluorinated in the nucleus or the oxidation of CHCl groups for the production of carboxylic acid chlorides.

Production of carboxylic acid fluorides

Lower alkyl esters of 3-amino crotonates substituted by halogen in the C-4 position, e.g. ethyl 3-amino-4,4,4-trifluoro-crotonate, in which the amino group optionally may be substituted by one or two C1 to C3 alkyl groups or by one or two aryl groups, e.g. phenyl, are synthesized by thermolysis of ammonium salts of corresponding lower alkyl esters of acetoacetic acid substituted in the C-4 position by halogen, and removal of the resulting water of reaction. The water of reaction may be removed by an entraining agent, which preferably has a specific gravity heavier than that of the aqueous phase which forms in the reaction. This minimizes yield losses due to the ammonium salt becoming dissolved in the aqueous phase and results in especially high yields. Formation of the ammonium salt and thermolysis can be carried out simultaneously. Alternatively, it is possible to start from a molten ammonium salt of the halogencrotonate, e.g. the salt of the lower alkyl ester of 4,4,4-trifluoroacetoacetic acid, or to produce the salt in situ, and to pass an inert gas through the molten salt under thermolytic conditions and in the absence of a solvent. In this way the desired product can be produced in high yield and in high purity. This alternative can be implemented as a continuous process.

Production of aminohalogencrotonates

The production of a potassium fluoroaluminate having a low melting point, which can be used as a flux when soldering aluminum. The potassium fluoroaluminate is prepared in an aqueous medium from aluminum hydroxide, hydrogen fluoride and potassium hydroxide in a molar ratio of aluminum:fluorine:potassium of approximately 1:5:2. After drying at 80&deg; C. under vacuum, the resulting potassium fluoroaluminate has a differential scanning calorimetry melting point of about 548&deg; C.

Low-melting potassium fluoroaluminate

A flux which contains irreversibly dehydrated K,AlF,, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Flux suitable for soldering light metals such as aluminum

Process for preparing flux suitable for soldering light metals such as aluminum

The production of a potassium fluoroaluminate having a low melting point, which can be used as a flux when soldering aluminum. The potassium fluoroaluminate is prepared in an aqueous medium from aluminum hydroxide, hydrogen fluoride and potassium hydroxide in a molar ratio of aluminum:fluorine:potassium of approximately 1:5:2. After drying at 80.degree. C. under vacuum, the resulting potassium fluoroaluminate has a differential scanning calorimetry melting point of about 548.degree. C.

A flux which contains irreversibly dehydrated K.sub.2 AlF.sub.5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Difluorochloracetyl, dichloracetyl and trichloracetyl chloride

The addition of hydrogen fluoride to unsaturated C--C groups and the chlorine-fluorine exchange on perhalogenated carbon atoms can be advantageously catalyzed by a catalyst mixture which comprises at least partially fluorinated titanium halide in combination with tin (IV) halide.

Catalytic mixtures composed of titanium and tin and uses thereof

A method for preparing lithium hexafluorophosphate, which is useful as an electrolyte in primary and secondary cells, involves combining and cooling phosphorus pentachloride and lithium fluoride, and then adding hydrogen fluoride. Using this method, which is simple to perform, a good yield of the product can be obtained.

Method of preparing LiPF.sub.6

Metal structures, e.g. coolers or heat exchangers, can be produced by placing together metal components coated with solder, dipping them into a slurry of a flux, and soldering them by heating. Alternatively, components coated with solder can also be coated with flux, then placed together to form the metal structure and soldered by heating. In this case, however, the flux must be applied so as to adhere securely, and to this end in the prior art the flux has been 'glued on' to the metal surface by organic or other binders, which when burned out during the soldering process can produce undesirable exhaust gases or emissions. The present invention discloses a metal component which is provided with a sintered flux coating which adheres without binder. The coating can optionally also contain solder metal or other auxiliaries dispersed therein. The coating is applied, for example, by contacting the metal component with a binder-free slurry of the flux or dry coating the metal component electrostatically, and then heating the coated component while avoiding melting of the flux, so that an adherent sintered flux coating is formed on the metal component. The use of these coated metal components for the production of soldered metal structures and metal structures obtained using such components are also described. Potassium fluoroaluminate flux is particularly advantageously used.

Flux-coated metal components

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Hanover, Germany

Werner Rudolph